Such hydraulic pilot control units having pressure-regulating valves serve, in particular, for pressurizing and therefore adjusting valve spools of valves or main stages, which are subjected to relatively high pressure forces. For this purpose the pilot control units comprise joysticks or handles, which serve for adjusting the respective control pistons of the pressure-regulating valves.
DE 196 22 948 A1 shows a pressure-regulating valve of such a hydraulic pilot control unit. Here (according to FIG. 1) a control pressure present acting on the connection P is transmitted wholly or partially to a working connection A, when a control piston is displaced in an opening direction by a tappet.
One disadvantage to such hydraulic pilot control units is that oscillations can be induced in the control piston here by pressure acting on various surfaces and by various springs. This is exacerbated by the fact that the control piston is composed of iron and thereby has a relatively large mass. Furthermore, the inducement of oscillations is exacerbated in that the control piston has a relatively long neck, via which a main portion of the control piston is connected to the tappet.
DE 103 24 051 A1 shows a pressure-reducing valve, the control piston of which, embodied as a stepped piston, is relatively heavily damped. For this purpose a damping passage is provided with a damping pin. This increases the stability of the feedback loop, but at the same time also presents disadvantages, such as a slower response speed, for example.
A further possible way of increasing the stability is to reduce the gain of the feedback loop in accordance with FR 2 857 705 B1.
In the light of this, the object of the disclosure is to create a hydraulic pilot control unit having at least one pressure-regulating valve, in which the stability of the feedback loop is increased through a directly acting parameter.
This object is achieved by a hydraulic pilot control unit having the features described herein.